The automotive industry is continually striving to attain reductions in engine fuel consumption and among the various systems and devices proposed heretofore by the prior art is the use of a duty-cycle type of electromagnetic fuel metering valving assembly. Generally, as is well known in the art, such duty-cycle valving assemblies employ a generally cyclically energized field coil which causes an associated armature-positioned valving member to open and close against a cooperating valve seating surface to intermittently permit and cease fuel flow to the engine. Generally, the average amount of time, within a given span of time, that the valve is opened will determine the then metered rate of fuel flow to the engine.
In such fluid flow metering devices it is important to establish and regulate the pressure of the fluid, in this case fuel, upstream of the cooperating valving member and valve seating surface in order to establish the desired rate of metered fluid flow for a given duty-cycle.
Heretofore, the prior art has, in the production of fuel injection systems and apparatus, separately flow calibrated the fuel injector assembly and separately calibrated the attendant pressure regulator assembly. Often each of such is calibrated with respect to a nominally same magnitude of reference pressure. In any event, in so doing each of the assemblies has its own tolerance to which it is individually calibrated and, as a consequence thereof, the calibrated injector assembly must be subsequently matched to the calibrated pressure regulator assembly or, in the alternative in order to avoid the requirement of matching, the respective initial calibration tolerances of the injector assembly and of the pressure regulator assembly are made somewhat hypercritical. Both of such approaches are not only time consuming but expensive.
The invention as herein disclosed and described is primarily directed to the solution of the aforestated problems of the prior art and to provide structure which is comparatively inexpensive to produce and yet provide the required regulated fuel pressure as to, in turn, provide for accurate metering of the fuel to the associated engine, as well as the solution of other related and attendant problems.